Cue-induced urge is a hurdle to quitting cigarette smoking. The overall aim of this project is to understand the role of visceral representation in cue-induced smoking urge. The model for this process is based upon Damasio's framework for emotion, which points to visceral representation as a central component in the process of feeling emotion. Cue-induced urge is associated with cue-induced visceral responses. The insular cortex is hypothesized to map cue-induced visceral responses and convey this representation to conscious experience as a feeling of urge. This hypothesis will be tested in two studies. The first study will combine positron emission tomography, autonomic psychophysiology and self-report measurement in order to reveal the neural correlates of cue-induced smoking urge and to quantify the relationships between insular cortex activity, visceral responses and feelings of urge. The second study will look at the effects of focal lesions in smokers in order to determine if the insular cortex is necessary for visceral responses and/or feelings of urge.